Incentive spirometers that communicate to patients the velocity or strength of a single breath are known in the art. Such incentive spirometers are used to train patients to breathe on their own after their breathing has been aided for a period of time by, for example, a respirator. However, prior art incentive spirometers do not necessarily help patients regain their lost lung capacity inasmuch as these spirometers do not enable patients to gauge their progress in this regard while breathing under their own power and according to their own capability.
Incentive spirometers heretofore known in the art have a traditional flow meter type of indicator in which a ball is suspended in a translucent or transparent column when air is being drawn through the spirometer. The position of the ball or similar object indicates that air is flowing through the spirometer. The closer the ball to the top of the column, the greater the velocity of the air being drawn through the column.
The flaw in the prior art spirometers is that they fail to indicate the volume of air being drawn by the patient into their lungs during a particular time period. Yet, the therapeutic value of the spirometer could be enhanced if a patient or therapist can gauge how much air is being drawn into the patient's lungs.
Also, the prior art spirometers do not provide the proper incentive, as they tend to make the patient want to breathe in a fashion that will draw the indicator up as high as possible in the gauge based on the velocity of the inhaled or exhaled air. When a patient with reduced lung capacity "fills" his or her lungs in this manner, a comparable amount of time and effort must be spent exhaling. This sporadic, deep breathing does not train the patient to breathe normally. As a result, though individual breaths may be taken at maximum flow indicated by the spirometers of the prior art, the total volume of air inhaled by the patient may not be increasing. Because the prior art spirometers do not indicate total volumetric flow, the patient or therapist may not necessarily realize that the patient's lung capacity is not improving during therapy.
Furthermore, prior art spirometers cannot be used to dispense medication because the total air flow cannot be measured. Most medication can only be administered in dosages that are measured by the volume of air administered with the dosage. Medication administered in too concentrated a dosage will be wasted and can have harmful effects as well. Medication administered in too low a dosage will be ineffective. Therefore, a spirometer that indicates the volume of air therethrough during any given time period is necessary to administer medication to a patient.